Blind stitch sewing machines



Feb 20, 1934. c w. MUELLER 1,947,950

BLIND STITCH SEWING MACHINES Filed Dec. 15, 1931 5 Sheets-Sheet 1 o 24- a o (:2) f o .11 o 15 Q INVENTOR BY fin 7 A TTORNE Y Feb. 20,1934. c; w, MUELLER 1,947,950

BLIND STITCH SEWING MACHINES Filed D80. 15, 1931 Sheets-Sheet 2 2 5% a p 20 g 66 in; I, A 26 44 1" K I a 4.2 I 59 I 4/ G 61 2 1: 66 f w 22 a 45 aka/1km- 19 1 -INVENTOR A TTORNE Y Feb. 20, 1934.

c. w. MUELLER BLIND STITCH SEWING MACHINES Filed Dec. 15, 1931 5 Sheets-Sheet 5 INIVENTOIR A TTORNE Y Feb. 20, 1934.

c'. w. MUELLER BLIND STITCH SEWING MACHINES Filed Dec. 15, 1931 5 Sheets-Sheet 4 fja.

I a F? INVENT OR BY 5T "75 ATTORNEY Feb. 20, 1934. c, w MUELLER 1,947,950

31mm STITCH SEWING MACHINES 5 Sheets-Sheet 5 Filed Dec. l5, 1931 INVENTOR Patented FebfZO, 1 934 1,941,950 I BLIND STITCH SEWING MACHINES Charles W. Mueller, St. Louis, Mo., assignor to Lewis Invisible Stitch Machine Company, St. Louis, Mo., a corporation of Maine Application December 15, 1931. Serial No. 581,218

' 15 Claims.

This invention relates to new and useful improvements in blind stitch sewing machines and has for some of its objects the provision'of a lower 4-motion feeding mechanism, a vertically reciprocatory work clamp, and an oscillatory ridge forming element, all mounted on a depressible work support located below a stationary presser foot, in combination with driving connections between the main shaft and the feeding mechanism, the work clamp and the ridge forming element which permit of thework support to be depressed without disconnecting the driving connections; to provide means for oscillating the ridge forming disc simultaneously and in unison with the feeding stroke of the feed dog, and to provide a single adjustmentfor simultaneously and uniformly varying the feed stroke of the feed dog and the oscillating movement of the ridge forming element.

2o 1 With these and other objects in view which will more fully appear, thenature' of'the invention willbe more clearly understood by following thedescription, the appended claims, and the several views illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a top plan view of a sewing machine constructed in accordance with my invention,

Figure 2 is a left hand elevation thereof,

Figure 3 is a front elevation of the machinethe 'work support being'shown in section to better disclose the operating mechanism carried thereby,

Figure 4 is a view partly in elevation and partly on the line 4-4 of twinbottom plan view taken Figure 2,

Figure 5 is a vertical cross sectional view taken on the line 55 of Figure 1,

r i Figure 6 is an enlarged end elevation showing do, particularly the presser, foot, the feeding mechanism, the work clamp; and the ridge forming elem Figure 7115 a vertical sectional view taken on .the line 1541 of Figure-3, 45. Figure 8 is a partial top plan view of the presser i.foo't,-'the view also showing the looper, the needle,

" the-work clamp, and the ridge forming element,

Figure 9 is a plan view of the work clamp, the ,feed dog, and the ridge forming element, Figure 10 is a detail vertical sectional view taken on the line 10-10 of Figure 6, and

Figure 11 is a view showing in perspective the work clamp, feed dog mechanism, and ridge forming element in separated relation.

55 Like reference numerals designate correspondto this arm is a needle-15, the oscillation of the ing parts throughout the several figures of the drawings.

Referring to the accompanying drawings, my improved sewing machine includes a frame A which comprises a base 5 having a'post 6 extendo0 ing upwardly from the rear right hand corner thereof, a horizontal arm 7 which extends laterally from the upper end of the post 6 and overhangs the left hand edge of the base 5, and a horizontal arm 8 which extends forwardly from 55 the overhanging end of the arm '7. Integral with the base 5 and extendingupwardly there from are two standards 9, 9 which are disposed at the right of the arm 8 and in front of the arm 7, and in a plane parallel with said arm '7. 7

"Journaled in the arm 7 is a main rotary shaft 10 and mounted for oscillations in the arm 8 is a needle shaft 11 which is operatively connected to the main shaft 1.0 by the usual mechanism not shown. Fixedly secured to thefree end of the arm 8 is a horizontally disposed and stationary presser foot 12 having an elongated opening 13 formed therein. Fixed to the front end of the needle shaft 11 is a needle arm 14 and fixed shaft 11 causing the needle to reciprocate in a plane extending across the elongated opening 13 of the presser foot. Cooperating with the needle 15 and actuated from the main shaft 10 by any suitable mechanism is a looper 16 for assisting the needle forming a line of single thread chain stitches. Although, I have shown and disclosed aistitch forming mechanism for producing single thread chain stitches, it is obvious that other stitch forming mechanisms may be substituted, if desired.

A depressible work supportl'l is fixed to a horizontal shaft 18 journaled in the standards 9, 9, the work support having its left hand end disposed under the presser foot 12. The work support is adapted to be swung downwardly in front of the standards 9 and is yieldably retained against downward movement by a coil spring 19 having one end engaging with a hook 20 whose shank is threaded into a lug 21 formed on the base 5, the other end of the spring bearing against the under face of the work support. The work support 17 is provided at one end with a depending stop arm 22'which is adapted to engage an adjustable stop screw 23 threadably engaged in a lug 24 carried by the base 5 and thereby limit the upward movement of the work arm 17 under the influence of the coil spring 19. Disposed below the foot 12 and cooperating therewith is a work clamp 25 having a longitudi- 11c in this art.

nally extending opening 26 formed therein, said opening registering with the opening 13 of the presser foot for the purpose of receiving a ridge forming element or disc 27 which is fixed to a rock shaft 28 journaled in suitable bearings formed on the under side of the work support 17. The work clamp 25 is also formed with two feed dog slots 29 and 30, the former being disposed in rear of the disc receiving opening 26 and the latter extending along one side of said opening to a point in rear thereof. The work clamp 25 is rigidly secured at its front end to a vertically disposed supporting post 31 which is mounted in a vertical bearing or bushing 32 located in the end of the work support 17 directly under the presser foot. The lower end of the post 31 projects below the lower face of the work support and secured to the projecting lower end of said post is a cross pin 33. Coil springs 34, 34 are seated within vertical bores 35, 35 formed in the work support 17 on opposite sides of the bushing 32 and havetheir upper ends anchored to the work support by' pins 34 .34 the lower ends of said springs being connected to the opposite ends of the cross pin 33. Thus the work clamp 25 is normally and yieldably urged upwardly into engaging relation with the bottom face of the presser foot 12.

A 4-motion feed dog 36 includes feed sections 37 and 38 whichare respectively disposed within the feed slots 29 and 30 of the work clamp 25. Means are provided for imparting four motions to the feed dog 36, that is, back and forth movements and up and down movements, the component of these four movements completing a feeding cycle as is well known to those skilled To this end, a feed travel shaft 39 and a feed lift shaft 40 are Journaled in bearing lugs depending from the under face of the work support 17. Fixed to the left hand end of the feed travel shaft 39 is a crank arm 41, and a substantially horizontal and rearwardly extending crank arm 42 is fixed to the feed lift shaft 40. A horizontal lift lever 43 has its rear end connected to the horizontal crank arm 42 by a sliding pivot 43 and has its front end disposed in advance of the feed lift shaft 40 and fulcrumed to the cross pin 33. A feed bar 44 is'pivotally connected at its rear end as at 45 to the crank arm 41. The front end of the feed bar 44 is pivotally connected as at 46 to the rear end of the feed dog 36. A lift link 47 is pivotally connected at its upper end as at 48 to the front end of the feed dog 36 and at its lower end as at 49 to the lift lever. 43 at a point intermediate the feed lift shaft 40 and the work clamp post 31. The pivots 45, 46 and 48 thus form a toggle connection for the feed dog. The feed dog is provided at its front end with a downwardly extending arm 50 to which the upper end of a coil spring 51 is connected, the lower end of said spring .being connected to a pin 52 fixed to the lower end of the lift link 47. Thus, it will be seen that the feed dog is pivotally connected to the feed bar 44 and that the spring 51 yieldably retains the feed dog in proper engagement with the presser foot, the mounting of the feed dog, however, permitting the same to swing and thereby accommodate itself to seams in the material when the latter is being fed through the machine.

The feed travel shaft 39 and the feed lift shaft 40 are oscillated by separate connections from themain shaft 10 and its front end adjustably connected by a clamp bolt 55 to the slotted rock arm 53. By adjusting the bolt 55 along the slot of the arm 53 the amount of oscillation to the feed travel shaft 39 may be varied and consequent y the length of the feed stroke of the feed dog 36 may be correspondingly varied. Fixed to the feed lift shaft 40 is a rock arm 56 to which is pit tal- 1y connected as at 57 the forward end of a pitman 58, the rear end thereof being eccentrically connected to the main shaft 10.

The ridge forming disc or element 27 is sector shaped in side elevation and includes a rear radial wall 59 which merges with the concentric periphery 60 of the disc. It is desirable to oscillate the disc 27 simultaneously and in unison with the back and forth movements of the feed dog 36 whereby a ridge or node will be formed in the material during each feeding cycle. To this end, the disc supporting shaft 28 is oscillated from the feed travel shaft 39 through the medium of crank arms 61 and 62 which are fixed to the shafts 23 and 39 and project radially in the same direction therefrom, together with a link 63 which is pivotally connected to the same crank arms.

In operation,- the material to be seamed or felled is inserted under the presser foot 12 and above the work clamp 25. For this purpose, the work support 17 is depressed and it will be noted that when the work support is thus depressed, the 103 work clamp 25, the ridge forming element 27, the feed dog 36, the oscillatory shafts 28, 39 and 40, together with the connected driving devicesbetween the various parts are all movable downwardly with the work support and without i110 connecting said parts from the main shaft 10.

The work clamp 25 is vertically reciprocated alternately with the up and down movements of the feed dog 36 as will be readily understood. When the work clamp 25 is lowered, the feed dog 11$ 36 is partaking of its feeding stroke and simultaneously therewith the ridge forming element 27 is oscillated to project a. ridge of material into the opening 13 of the presser foot 12 and feed said ridge rearwardly into needle penetrating 12) position. At the end of the feed stroke, the work clamp 25 is moved upwardly to clamp the material against the presser foot 12 while the feed dog 36 and the ridge forming disc 27 are moved forwardly. The rear radial edge 59 of the disc is located in rear of the path of movement of the needle when said disc is at the rear end of its oscillations and consequently the disc supports the ridge .of material for a sufficient time to insure the needle entering the ridge during the first part of the forward oscillatory movement of the disc. It will be noted that during the penetrating stroke of the needle the material is clamped between the presser foot and the work clamp and consequently the ridge of material is held against 136 the thrust of the needle.

It is of course to be understood that the details of structure and arrangements of parts may be variously changed and modified without depart ing from the spirit and scope of my invention. 146

I claim:-

1. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscil- 1 latory disc supported below the foot for projecting a ridge ,of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position; and means for imparting the backward and forward movements to the feed dog simultaneously with the backward and forward oscillatory movements of the ridge forming element.

2. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting aridge of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position; and means for imparting the backward and forward movements to the feed dog in unison with the backward and forward oscillatory movements of the ridge forming element.

3. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the'needle; a e-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position; means for actuating the feed dog including an oscillatory shaft and connections between the dog and shaft for imparting backward and forward movements to the dog; and driving connections between the disc and the shaft for oscillating the former.

4. In a blind stitch sewing, machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supporting shaft mounted below the foot; a disc fixed to said shaft for projecting a ridge of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position; and means for actuating the feed dog including a feed travel shaft and a feed lift shaft disposed below the foot and arranged in parallelism with the disc supporting shaft, rockarms respectively fixed to the feed travel shaft and to the disc supporting shaft and projecting radially in the same general direction from their shafts, and a link connecting the rockarms.

5. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; a verticallyreciprocatory work clamp disposed below the foot for cooperation therewith; a 4-motion feed dog disposed below the foot and cooperating therewith to feed the ridge of material into needle penetrating position; actuating means for imparting to the feed dog up and down and backward and forward movements, connections between the feed dog actuating means and the work clamp for reciprocating the latter alternately with the up and down movements of the feed dog; and connections between the feed dog actuating means and the disc for oscillating the latter in unison with the backward and forward movements of the feed dog.

6. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; and a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position, said feed dog having a feed section disposed in rear of the ridge forming disc and another feed section disposed along one side of said disc.

7. In a blind stitch sewing machine; the com bination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position, said feed dog having a feed section disposed in rear of the ridge forming disc and another feed section disposed along one side of said disc; a work clamp provided with a longitudinally' extending opening for receiving the ridge forming disc and with feed slots for receiving the feed sections of the feed dog, one of the slots being disposed in rear of the opening and the other of said slots being disposed along one side of said opening; means for vertically reciprocating the work clamp alternately with the up and down movements of the feed dog; and means for oscillating the disc in unison with the backward and forward movements of the feed dog.

' 8. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; a vertically reciprocatory work clamp disposed below the foot for cooperation therewith and including a vertically movable post; means for feeding the ridge of material into needle penetrating position comprising a feed travel shaft and a feed lift shaft arranged in parallelism, a substantially vertical crank arm fixed to the feed travel shaft, a substantially horizontal and rearwardly extending crank arm fixed to the feed lift shaft, a horizontal lift lever having its rear end connected to the horizontal crank arm by a sliding pivot and having its front 'clamp post, a horizontal feed bar pivoted at its rear end to the'vertical crank arm, a vertical lift link pivoted at its upper end to the feed bar and at its lower end to the lift lever intermediate the feed lift'shaft and the work clamp post, and a feed dog mounted on the feed bar; and connectionsbetween the disc and the feed travel shaft for oscillating the disc in unison with the backward and forward movements of the feed dog.

9. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position;and means for imparting the backward and forward movements to the feed dog in unison with the oscillatory movements of the ridge forming element, and including means for simultaneously and uniformly varying the amount of oscillation of the disc and the backward and forward movement of the feed dog.

10. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supporting shaft mounted below the foot; a disc fixed to said shaft for projecting a ridge of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position; means for actuating the feed dog including a feed travel shaft and a feed lift shaft disposed below the foot and arranged in parallelism with the disc supporting shaft, rock arms respectively fixed to the feed travel shaft and to the disc supporting shaft and project ng radially in the same general direction from their shafts, and a link connecting the 'rock arms; a main shaft; driving connections between the feed lift shaft and the main shaft; and driving connections between the feed travel shaft and the main shaft.

11. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supporting shaft mounted below the foot; a disc fixed to said shaft for projecting a ridge of material upwardly through the foot into the path of the needle; a 4-motion feed dog disposed below and cooperating with the foot to feed the ridge of material into needle penetrating position; means for actuating the feed dog including a feed travel shaft and a feed lift shaft disposed below the foot and arranged in parallelism with the disc supporting shaft, rock arms respectively fixed to the feed travel shaft and to the disc supporting shaft and projecting radially in the same general direction from their shafts, and a link connecting the rock arms; a main shaft; driving connections between the feed lift shaft and the main shaft; and driving connections between the feed travel shaft and the main shaft including a slotted rock arm fixed 'to thefeed travel shaft and a pitrnan eccentrically connected at one end to the main shaft and having its other end adjustably connected to said slotted rock arm.

12. In a blind stitch sewing machine; the combination with a stationary presser foot; of a stitch forming mechanism operating thereabove and including a reciprocatory needle; an oscillatory disc supported below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; and a feeding mechanism disposed below the foot and cooperating therewith to feed the ridge of material into needle penetrating position includinga feed bar,

of a stationary presser foot attached to said head; a main shaft journaled on the frame; a depressible work support disposed under said foot; a stitch forming mechanism supported on the head above the foot and including a reciprocatory needle; an oscillatory disc mounted on the work support below the foot for projecting a ridge ,of material upwardly through the foot into the path of the needle; a 4-motion feed dog mounted on the work support below the foot and cooperating therewith to feed the ridge of material into needle penetrating position; and driving connections efiectively maintained between the disc and. the feed dog, and the main shaft regardless of the position of the work support;

14. In a blind stitch sewing machine; the combination with a frame including a stitching head, of a stationary presser foot attached to said head; a main shaft journaled on' the frame; a depressible work support disposed under said foot; a stitch forming mechanism supported on the head above the foot and including a reciprocatory needle; an oscillatory disc mounted on the work support below the foot for projecting a ridge of material upwardly through the foot into the path of the needle; a d-rnotion feed dog mounted on the work support below the foot and cooperating therewith to feed the ridge of material into needle penetrating position; means for imparting backward and forward and up and down movements to the feed dog including two oscillatory shafts joumaled on the work support and disposed-in parallelism with the main shaft; and operating connections between the oscillatory shafts and the main shaft; and driving connections between the disc and one of the shafts for oscillating the disc.

15. In a blind stitch sewing machine the combination with a frame including a stitching head; of a stationary presser foot attached to said head; a main shaft journaled on the frame;

a depressible work support disposed under said foot; a stitch forming mechanism supported on the head above the foot and including a reciprocatoryneedle; an oscillatory disc mounted on the work support below the foot for projecting a idge of material upwardly through the foot into the path of the needle; 9. 4-motion feed dog mounted on the work support below the foot and cooperating therewith to feed the ridge of material into needle penetrating position; means for imparting backward and forward and up and down movements to the feed dog including two oscillatory shafts journaled on the work support and disposed in parallelism with the main shaft, and operating connections between the oscillatory shafts and the main shaft; a discsupporting shaft journaled on the work support and disposed in parallelism with the oscillating 5 shafts; and a connection between the disc-supporting shaft and one of the oscillating shafts for oscillating the former.

CHARLES w. MUELLER. 

